Performance enhancement of the lateral flow immunoassay by use of composite nanoparticles as signal labels

The lateral flow immunoassay (LFIA) strip has been one of the classic but dominant tools in the point of care (POC) detection with multiple advantages (e.g., portability and simplicity). As the signal labels in LFIA, colored nanomaterials (CNMs) such as colloidal gold nanoparticles (AuNPs) have been used broadly despite limited sensing potential (e.g., in terms of low-signal intensity and poor sensitivity). In this respect, the practical utility of the composite nanoparticles (CPNPs: e.g., Fe3O4@AuNPs, SiO2@Quantum dots, and Au@Pt) has been recognized as their alternatives in terms of sensitivity enhancement, signal readout diversity, anti-matrix interference, and cost-effectiveness. The incorporation of CPNPs with LFIA is expected to help expand their applications in diverse fields. The superiority of CPNPs over the existing conventional NMs is also discussed along with the present challenges and future directions in this research field.